End of Life Ruby 3.1 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

Module#singleton_class?

mod.singleton_class? → true or false

static VALUE
rb_mod_singleton_p(VALUE klass)
{
    return RBOOL(RB_TYPE_P(klass, T_CLASS) && FL_TEST(klass, FL_SINGLETON));
}

Returns true if mod is a singleton class or false if it is an ordinary class or module.

Example

class C
end
C.singleton_class?                  #=> false
C.singleton_class.singleton_class?  #=> true

See also #ruby2_keywords #to_s #remove_method #undef_method also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.0